Coordinated control of the DFIG wind power generating system under unbalance gird voltage conditions

This paper proposes a coordinated control strategy of the rotor side converter (RSC) and grid side converter (GSC) of the doubly-fed induction generator (DFIG) based wind generation systems under unbalance voltage conditions. Mathematical models and system behaviors of the RSC and GSC under unbalanced voltage are illustrated. The reason why the rotor side converter has its limitation can be obtained by the analysis result of the mathematical model. In particular the control strategy, which the rotor side converter´s aim is taking the pulsations of electromagnetic torque, and the gird side converter can smooth the total output power and the DC bus voltage. Simulation demonstrates the exactitude and effectiveness of the proposed control algorithm.